November  Aye, There's the Rub

Young trees, beware -- it's rutting season for white-tailed deer (Odocoileus virginianus) and other ungulates. During the rut, bucks rub their antlers on trees and shrubs, spar with other bucks and pursue females. The purpose of rubbing trees is to leave both a visual and an olfactory mark as a means of attracting females and deterring other males. Bucks rub their antlers on just about anything, but especially smooth-barked small trees. In so doing, they deposit oils from a scent glad at the base of the antlers. At the same location, the bucks may also scratch the ground and urinate, as further marking. The more fit the deer, the larger the antlers and the more it rubs. People often think that the number of points on a buck indicates the age, but the size of the rack actually has more to do with genetics and food quality. Age can only be positively ascertained from the teeth.

If you have some nice young trees or shrubs you planted this year, you might want to protect them from rubbing as well as winter deer browsing. Rubbing removes the outer bark, and depending on the size of the tree can seriously damage it or kill it. Browsing will not typically kill a tree or shrub, but may significantly set it back or cause it to have an undesirable shape. A healthy deer can eat 10-12 lbs of twigs per day, with a preference for smaller branches and seedlings. Unfortunately, they do not care much for the most abundant shrub in the woods -- the non-native species, common buckthorn.

Given the opportunity for a little extra protein, white-tailed deer will stray from their normal vegetarian diet. People who mist-net birds for banding occasionally encounter the soggy remains of small birds that had been caught in the net -- and consumed by passing deer. Apparently deer can also can catch fish in shallow streams, and are known to dig through snow to eat colonies of winter ladybug beetles! Who knew?

While white-tailed deer can live 15 years or more, a lifespan of about six years may be more typical for deer that are over-populated and subject to hunting and other pressures.

References:

E. H. Williams Jr. 2005. The nature handbook  a guide to observing the great outdoors. Oxford University Press, New York, NY.